A three-day refreshment walking here and there was much helpful in retreatment of my tired body and head. Yeah . . . I was thinking about Zen V4.

Many nice diy audio pictures . . . Err . . . I post my picture even if this is not an audio. Yesterday I took this in Gulangyu Island, Xiamen, where after the Opium War in 1814, 13 countries including GB, France, Japan established consulates, churches and hospitals. My look in the picture is much better than the real shape ^^.

after some tweaking,you'll bang on topology limits ;
if you can find your source characteristics and output amp sensitivity in with topology layed boundaries .......fine ;
if not...... nice xperiment ,useful as stage somewhere.

Quote:

Originally posted by Steenoe
Good job, Manu. Nice little board
Multiturn trimmers will assist in an easier adjustment. You can pretty easily go past the sweet spot with a singleturn pot. [/B]

Thank You for the hints. I will try them all and report.
But for now I have to go to work...
Manu

PS : Maybe it was not clear from my post yesterday, so I wanted to point out again that in spite of all this little opportunities (problems) I found the sound having a special magic: the Germans would say "quicklebendig" and the French would say "limpide".

Hi,
this thread gave me an idea to make a simple preamp for OPA549 (sounds very good in inverting topology with a gain of 6 dB - 2x). One JFET alone couldn't do it so I used a BJT to help. Output from my DAC (AK4393) is 2.4 AC V peak and this preamp gives on output 12.5 AC V peak which is enough to drive the OPA549.
First, I simulated the circuit in Circuit Maker 2000 with parts that I had in drawer, and fortunately, the real circuit measured roughly the same.
BF245C is a bit different from 2SK170, but that's what I have at hand.
I tried BC560C and BC639 for Q5, but ZTX550 is the best in this place (needs a heatsink). In the next couple of days I'll try to find a BD139 or something similar to try it.
Sound is great, still neutral but gives more space and instruments' localisation compared to AD823 and AD797 which I used before.
I used IRF610 as power supply voltage regulator as I have them in drawer, otherwise LM317 or something similar can be used.

Manu, what amplifier did you connect Jfet BOZ to? Maybe the reason for distortion is the high sensitivity of the amplifeir,and it simply gets too much...
I am planning to modify (again) my 'F2 lite' into OTA ( a follower with zero voltage gain). Even though F2 lite is a nice amp, I have converted Zen v9 into transconductance amp, so I don need two transconductance amps.... (yes I know, there's always a possibility to send one to Choky for proper disposal, but it's too heavy )

Quote:

Originally posted by Babowana My look in the picture is much better than the real shape ^^.

Heheheh....Some people look better on photos than real life, and vice versa....

I guess that a nice background has an effect, too. Really nice (the background)

Very nice work Manu, looking forward to hearing further impressions. My system is taken apart at the moment due to construction in the house, but I have my missing resistors and a few other items arriving today.

Originally posted by Zen Mod
if you can find your source characteristics and output amp sensitivity in with topology layed boundaries .......fine ;
if not...... nice xperiment ,useful as stage somewhere.

The tech specs of my SA7001 SACD says the output level is 2,3V RMS, and for the Amp, its an Aleph 5 (40V 2,1 bias - pretty hot this days, so if you have some saussages (or cevapi) left.... c )
Thx for your hints. Should I let the drain res at 2K2 if I reduce the Source res to may be 6R?
Manu

mpmarino :
thx

twitchie:
Glad to hear you found at least your missimg 1M resistors. : There is always something one doesn't have in Stock - I have to order some good 25K pots, mine are definitively sh.... no idea why and when I did buy them.